Ingot mold insert and method of making the same



Sept. 25, 1956 H. D. STERICK 2,763,906

INGOT MOLD INSERT AND METHOD OF MAKING THE SAME Filed NOV. 19, 1951 INVENTOR.

HARRISON D. STE RICK.

ATTORNEYS.

like openings over the area of the mat.

United States Patent O INGOT MOLD INSERT AND METHOD OF MAKING THE SAME Harrison D. Sterick, Pittsburgh, Pa.,

Application November 19, 1951, Serial No. 257,039 8 Claims. c1. 22-139 This invention relates to an ingot mold insert and a method of making the same, and is for an improvement in inserts of the type disclosed in the patent to William E. Schmertz, No. 2,453,643, granted November 9, 1948.

In the above-mentioned patent, the insert comprises a mat formed by simultaneously coiling a corrugated ribbon of metal and a flat ribbon of metal into a circular disc. The flat ribbon of metal, being thus interposed between the convolutionsof the corrugated ribbon, prevents the corrugations of one convolution from nesting into the corrugations of adjacent convolutions, and thereby maintains a uniform disposition of the small cell- This preventing of nesting and the maintenance of a uniform cell pattern is important because successful performance of such a mat is based on having the area-of the mat formed with numerous small spaces or pockets.

Mats of this kind are used only once since they become a part of the bottom end of the ingot which is subsequently cropped OE and re-melted, and are inseparably embedded in such end. Consequently'it is important that they be made as cheaply as possible. While the use of a flat strip and a corrugated strip in the manner disclosed in said patent produces a very satisfactory mat, it is a relatively expensive mat because the convolutions of the flat metal contribute very littleto the total area of the mat, while they do increase substantially the weight of the'mat.

In my copending application with William E. Schmertz, Serial No. 244,524, filed August 31, 1951, there is disclosed a mat formed from a single strip of metal specially shaped so as to preclude nestings of the corrugations of one convolution with those of the next. This requires a slower operation of deforming the ribbon from which the mat is formed, and also requires the use of more expensive dies and machinery, although it has certain other advantages.

The present invention provides a mat and a method of forming it, which eliminates the disadvantages of both the patent and the application. While it is formed of two ribbons of metal, it is much lighter in weight and has a relatively greater cell area than mats formed from a flat strip and a corrugated strip, but the operation of forming the strip is much less complicated than the strip disclosed in the said copending application.

According to my invention, a mat is formed by simultaneously coiling two ribbons of metal into a disclike form, but both ribbons are corrugated, and the corrugations, instead of extending transversely, are positioned on opposite diagonals or sloped in opposite directions in the adjacent convolutions, so that there can be no nesting. Hence both ribbons of metal contribute equally to the overall area of the disc, and the insert has a better arrangement of cells in that, instead of passing straight through the mat, they are of criss-cross form, in which the metal is more readily trapped and chilled.

The object of my invention therefore is to provide an 0 the mandrel and 6 is the table.

improved form of mold insert and an economical way of making same.

My invention may be more fully understood by reference to the accompanying drawings, in which:

Fig. 1 is a top plan view of two strips of metal brought together in face-to-face relation in accordance with my invention;

Fig. 2 is a side elevation of a fragment of one strip located in front of a fragment of another strip;

Fig. 3 is a fragmentary view showing a segment of a portion of the entire mat;

Fig. 4 shows one method of making the mat;

(Fig. 5 is a modification of the method shown in Fig. 4; an

Fig. 6 is a front elevation of a fragment of a strip of slightly modified form." a

In the accompanying drawings which are more or less schematic, the insert is of generally circular form, although after being made, it can be pressed into other shapes than circular, but it is most conveniently initially manufactured in circular form. In Fig. 3 the mat is designated generally as 2, and only a sector of the entire mat is shown, but it is to be understood that the mat is fully circular. It is comprised of two ribbons of metal which are designated 3 and 4, which are tightly wrapped or spiraled together. As shown in Figs. 1 and 2, the two strips. are preferably, but not necessarily, of equal width, and each is corrugated, but the corrugations in the ribbon 3 are inclined in one direction from the transverse axis of the strip, while the corrugations on the strip '4 are inclined at an opposite angle. Hence when two strips are pressed together in face-to-face relation, thecorrugations of one cross the corrugations of the other, and the corrugations of the adjacent convolutions cannot nest at any point. Hence the entire mold insert is conveniently formed of two strips of metal, each having diagonalcorrugations, the corrugations of one strip and in one convolution beingdiagonally disposed, and the corrugations of adjacent convolutions are at an angle to each other forming cells over the entire area of the mat. These cells, instead of extending straight through the mat in a direction normal to the surface of the mat, are inclined or criss-cross, so. that they more elfectivelyretard the flow of metal through the 'mat', giving it an opportunity to more readilyfreeze. Also with the strips arranged in this way, gases or air may more readily escape from the cells at the time of the initial pouring.

While I have specifically mentioned that there are two ribbons, there must be at least two, and more strips similarly arranged may be simultaneously wound into a mat if this is desired in forming the mat.

In Fig. 4 I have illustrated schematically an operation of forming the mat from the two strips of metal. In Fig. 4, 5 designates a core or mandrel projecting from the top of a flat revolving table 6. The ends of the two ribbons of metal 3 and 4 are secured in the mandrel, and as the table 6, which is preferably but not necessarily in a horizontal plane, rotates, the mat is wound about the mandrel into circular form. The two ribbons of metal 3 and 4 pass through two separate pairs of rolls 7 and 8 respectively, the teeth of one pair of rolls being diagonally arranged at an opposite angle to the teeth in the other set of rolls which are also diagonally arranged. Thus the two ribbons of metal are corrugated with the oppositely inclined corrugations as they are fed to the insert winding machine.

In Fig. 5 I have illustrated a modification of the arrangement shown in Fig. 4, in which 5 again designates Instead of there being two sets of rolls 7 and 8 as in Fig. 4, there is a single Set of rolls 9 having teeth arranged to produce diagonal corruga ions. in the two strips 3 and 4 as they pass through the rolls. One of the strips, such as 3, is then rotated through an arc of 180 before it is brought into conac with the other strip ttheing wound upon the table. This reversal or turning of the strip 3 through 180 effects he. opposite inclination of the corrugations in the W nvolu i ns so that one. set of rolls can be conveniently used. for corrugating both strips.

A dilfio lty encountered in mats of this kind is that they are formed from smooth ribbons. of metal and the nvolution are apt to slide one upon another in the ni h mat, o hat if the mat is picked. up at the. edge, unless care is xercised, the center, due to inertia, will tend to move up less quickly, deforming the mat: into a kind of an inverted come that may: hen unwind. In der o overcome this, the strips may be slightly roughened over their entire surface before they are corrugated, by pas ing thorn betwe n two rough rolls which form tiny craters and mounds on the surfaces thereof, or they may even be sand-blasted, or as shown in Fig. 6, o y the lower edge at each strip may e r u h n d o etched, or possibly one strip may have a r ughened rgin and another may not. The term roughening as used herein also includes dent-ing of the metal or simi ar y ak ng ligh def rmations hat des roy he absolu e. smoo h surface of he me al. The p rpo e of this roughening is to increase the friction be ween h jac n orrug ions or produc a light int rlocki thereof through chance. intermeshing of tiny peaks and recesses, so as to reduce the tendency of the insert to d form when it is being handle While I have shown and described one preferred mbodiment of my invention, it will be underst od ha th invention is not restricted to the exact form and arrangement of corrugations shown, but may be otherwise made and constructed within the. ontemplation, of my invention and under the scope of the. following claims.

I claim: c

1. A mold insert comprising a mat formed of. at leas two ribbons. of metal coiled together, both ribbons being corrugated, with the corrugations of one ribbon, being at an angle to those. of. the adjacent ribbon, the p edges of the two confronting strips presenting upwardly opening cells into which metal may fl similar cells bein 4 also formed between convolutions of the two strips.

2. A mold insert comprising a matformed of at least two ribbons of metal coiled together, both ribbons being corrugated, with the corrugations of one ribbon extending across the corrugations of the other ribbon, the top edges of the two confronting strips presenting upwardly opening cells into which metal may flow, similar cells being also formed between convolutions of the two strips.

3. A mold insert comprising a mat formed of at least two elongated narrow strips formed into a mat with the strips set edgewise to the plane of the mat of metal coiled together, both ribbons being corrugated, with the corrugations of both ribbons being diagonal to the axis of the strip, those of one ribbon extending in a diagonal direction opposite to those of the other, the top edges of the two confronting strips presenting upwardly opening cells into which me al may flow, similar cells being also formed between convolutions of the two strips.

4. A mold insert comprising a mat formed of at least two elongated narrow strips formed into a mat with the strips set edgewise to the plane of the mat and of corrugated metal with the corrugations and cells formed by the corrugations criss-erossing and being open between the two strips at the top of the mat to form cells between the two strips into which metal may flow.

5. A mold insert as defined in claim 4 in which an area of at least one of each of the two contacting strips is also roughened to increase friction between the two strips and retard slipping of one strip transversely upon another.

6. A mold mat as defined in claim 5 in which such roughening is along the marginal edge of the strip.

7. The method of forming a mold insert which comprises corrugating at least two metal strips with the corrugations extending from one edge of the strips across the major portion of their width with diagonal corrugations' and then winding them together in face-to-face relation as they are being wound into a flat coiled mat in which the corrugations of the two strips are at opposite angles and cross one another.

8. The method of forming amold mat as defined in claim 7 which comprises additionally roughing at least one of the strips to increase the friction between adjacent convolutions.

References Cited in the. tile of this patent UNITED STATES PATENTS 52,0,366 Leaver s May 22, 1894 574,157 Lungstrom Dec. 29, 1896 1,625,061 Trout Apr. 19, 1927 2,409,249 Brown Oct. 15, 1946 2,453,643. Schmertz. Nov. 9, 1948 

